Environment and Breast Cancer: Science Review

Evidence From Humans
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Dietary phytoestrogens and breast cancer risk
Keinan-Boker, L., van Der Schouw, Y. T., Grobbee, D. E., Peeters, P. H. Am J Clin Nutr. 2004. 79:2, 282-8.
Study design
Prospective cohort
Funding agency
Other: Zorg Onderzoek Nederland, World Cancer Rese
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Postmenopausal and premenopausal combined
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Women aged 50-69 years residing in Utrecht or its vicinity participating to a regional program for breast cancer screening (DUTCH/ Prospect-EPIC), who completed the questionnaire and gave informed consent. Ex: Extreme daily intake of calories, prevalent cancer at any site at the time of enrollment, and residency in areas not fully covered by the Comprehensive Cancer Center Middle Netherlands
Exposure Investigated
Exposures investigated
Phytoestrogens (Isoflavone, Lignans)
How exposure was measured
Questionnaire, self-administered, FFQ
Exposure assessment comment
The questionnaire was not specifically designed to estimate phytoestrogen intake and did not include questions about specifc items that contains high amount of phytoestrogens, consumption of phytoestrogens very low including in the highest quartile
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
Confounders considered
Other breast cancer risk factors, such as family history, age at first birth, and hormone replacement therapy use, that were taken into account in the study.
Not considered: Race, family history, BMI, menopausal status, alcohol consumption
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Description of major analysis
Adjusted HR with 95% CI, higher versus lower quartile of intake, subgroup for postmenopausal women, latency of 12 months, follow-up 4-8 years
Strength of associations reported
Isoflavones:0.98 (0.65-1.48); Lignans: 0.70 (0.46-1.09)
Results Comments
No protective effect of phytoestrogens against breast cancer.
Author address
Julius Center for Health Sciences and Primary Care, University Medical Center, Utrecht, Netherlands.